SP E-units: 1949 renumbering
1949 Renumbering:
In late 1949, the SP began a program to renumber its growing fleet of cab and booster units which had been mostly delivered in four unit ABBA sets with each locomotive in a set given an alpha suffix.
SP:
Cab units:
| 1949 numbers | Orig. numbers | |
| SP 6000-6004 | SP 6000A-6004A | |
| SP 6017 | SP 6011A |
Booster units:
| 1949 numbers | Orig. numbers | |
| SP 5900-5909 | SP 6000B,C-6004B,C | |
| SP 5916-5917 | SP 6011B,C |